The present invention relates to a multi-processor system and a program version upgrading method therefor. More particularly, it relates to a disk controller comprising a multi-processor system including a plurality of processors and a control program upgrading method therefor.
In the multi-processor system, processing of a job may be efficiently conducted by dividing the job among a plurality of processors for processing. As one form of application of the multi-processor system, a disk controller of a multi-processor configuration has been put into practice. Such a disk controller is disclosed in JP-A-2-62623. In the disk controller disclosed in JP-A-2-62623, a job such as reading or writing of data is distributedly executed by a processor which controls data transfer between a disk controller and a host computer, and a processor which controls data transfer between the disk controller and a disk drive. Specifically, for example, data read from one disk drive by one processor is transferred to the host computer by another processor. Thus, the data transfer process between the host computer and the disk controller and the data transfer process between the disk drive and the disk controller may be executed in parallel and efficient data transfer may be attained.
In the disk controller of the multi-processor configuration described above, it is possible to stop the processing by some processors and continue the data transfer control by the other processors to maintain fault processors. However, in such a maintenance method, it is a premise that the processors which distributedly process a job execute the same version of a program. When versions of the program to be executed by the respective processors are to be upgraded, and the maintenance is conducted in this manner, there occurs a period in which the programs of different versions co-exist and one job may be shared by the processors which execute the different versions of the program. In such a case, there may be no assurance of consistent processing of the job. As a result, when the versions of the program executed by the processors are to be upgraded, the system has to be wholly stopped.